malign
ma-lign
verb
To speak ill of someone, often falsely, to damage their reputation.
"He tried to malign her character publicly."
adjective
Having an evil or harmful nature or influence; malevolent.
"A malign influence spread through the group."
Thesaurus
Synonyms: malefic, evil, malevolent, maleficent, badmouth, drag through the mud, traduce, cancerous